CN106206639A - There is phase change memory and the manufacture method thereof of needle-like junction - Google Patents

Abstract

The present invention relates to phase change memory and the manufacture method thereof with needle-like junction.This device comprises the substrate containing access circuit and arranges at least one mnemon on the substrate, wherein this mnemon comprises and electrically connects with this access circuit and be arranged at the hearth electrode in the first dielectric layer, it is arranged at the first barrier layer between this hearth electrode and this first dielectric layer and this access circuit, extend from this hearth electrode and there is the heater of protuberance protruding from this first dielectric layer, being arranged in the second dielectric layer, wherein the sectional area of this protuberance is gradually reduced from lower to upper, and the end face of this protuberance is exposed to this second dielectric layer.Described method utilizes sacrifice layer to limit the projecting height of conductive material, refines the prominent conductive material heater with formation needle-like by etching technique, and then reduces the junction between heater and phase-transition material.The present invention can change the crystalline state of little scope phase-transition material with less electric current, therefore can reduce power consumption and avoid producing cavity.

Description

There is phase change memory and the manufacture method thereof of needle-like junction

Technical field

The present invention is to have needle-like about a kind of memory and manufacture method, particularly oneThe phase change memory of junction and manufacture method thereof.

Prior art

Phase change memory is a kind of Nonvolatile Random Access internal memory.Phase change memoryIn phase-transition material can pass through applying suitable electric current and between crystalline state and non-crystalline change.PhaseThe different conditions of change material (such as crystallization, hypocrystalline, noncrystalline) represents different resistance values.General andSpeech, non-crystalline person has higher resistance value compared to crystalline state person, and therefore, transit dose measuring resistance value is i.e.Data can be accessed.

In order to change the crystalline state of phase-transition material, with heater, phase-transition material must be heated.There is bigger junction, so between the heater of a kind of known phase change memory and phase-transition materialPreferably conductive characteristic can be obtained.But, make the phase-transition material Change-over knot crystalline state of bigger junction need biggerPower consumption, additionally, the crystalline state repeatedly changing phase-transition material easily produces cavity (void), cause productReliability reduces.Another kind of known phase change memory is then filling phase change material in tapered grooveMaterial, so that the junction between heater and phase-transition material reduces.But, said structure is filling phase changeDuring material, owing to bottom portion of groove is less, therefore easily form cavity because filling incomplete, again result in productThe reliability of product reduces or directly scraps.

In view of this, the junction between heater and phase-transition material how is manufactured less and reliableThe good phase change memory of property is the target that current pole need to be made great efforts.

Summary of the invention

The present invention provides a kind of phase change memory with needle-like junction and manufacture method thereof,It is to obtain the heater of needle-like by conductive material refinement, and then reduces between heater and phase-transition materialJunction.According to this structure, i.e. can change the crystalline state of little scope phase-transition material with less electric current, changeYan Zhi, the present invention not only can reduce power consumption, and can avoid producing cavity.

One embodiment of the invention provides a kind of phase change memory with needle-like junctionManufacture method, the method comprises: provide substrate, and it comprises access circuit, and wherein access circuit comprises at leastOne conductive junction point；The first dielectric layer is formed on substrate；Sacrifice layer is formed on the first dielectric layer；FormedAt least one runs through the through hole of the first dielectric layer and sacrifice layer, makes the conductive junction point of access circuit exposeCome；Sidewall in through hole forms the first barrier layer with bottom；Conductive material is filled in through hole, and with depositThe conductive junction point electrical connection of sense circuit；Remove sacrifice layer, make part the first barrier layer and conductive material highlightFirst dielectric layer；Remove the first barrier layer of prominent first dielectric layer；Part removes prominent first dielectric layerConductive material, to refine conductive material；Form the second dielectric layer in the first dielectric layer, and cover conductive material；And thinning the second dielectric layer, make conductive material exposed.

Another embodiment of the present invention provides the phase change memory with needle-like junction, this dressPut and comprise substrate and at least one mnemon.Substrate comprises access circuit.Mnemon is arranged at substrateOn.Mnemon comprises hearth electrode, the first barrier layer and heater.Hearth electrode electrically connects with access circuit,In wherein hearth electrode is arranged at the first dielectric layer.First barrier layer be arranged at hearth electrode and the first dielectric layer andBetween access circuit.Heater extends from hearth electrode, and has a protuberance and protrude from the first dielectric layer, prominentGoing out portion to be arranged in the second dielectric layer, wherein the sectional area of protuberance is gradually reduced from lower to upper, and protuberanceAn end face be exposed to the second dielectric layer.

Below by the accompanying drawing elaborate appended by specific embodiment cooperation, when being easier to understand thisThe purpose of invention, technology contents, feature and the effect reached thereof.

Accompanying drawing explanation

Fig. 1 a to Fig. 1 j is a schematic diagram, and show first embodiment of the invention has needle-like junctionThe manufacture method of phase change memory.

Fig. 2 a to Fig. 2 c is a schematic diagram, the phase change with needle-like junction of display second embodiment of the inventionThe manufacture method of memory.

Fig. 3 a and Fig. 3 b is a schematic diagram, the phase transformation with needle-like junction of display third embodiment of the inventionChange the manufacture method of memory.

Fig. 4 a and Fig. 4 b is a schematic diagram, the phase transformation with needle-like junction of display fourth embodiment of the inventionChange the manufacture method of memory.

Fig. 5 is a schematic diagram, the phase change memory dress with needle-like junction of display fifth embodiment of the inventionThe manufacture method put.

Fig. 6 is a schematic diagram, the phase change memory dress with needle-like junction of display sixth embodiment of the inventionThe structure put.

Fig. 7 is a schematic diagram, the phase change memory dress with needle-like junction of display seventh embodiment of the inventionThe structure put.

Detailed description of the invention

Hereinafter will be described various embodiments of the present invention, and coordinate accompanying drawing illustratively.Except theseOutside detailed description, the present invention also can be performed in other embodiment widely, any described embodimentSubstitute easily, revise, equivalence change is intended to be included within the scope of the present invention, and is as the criterion with claim.In the description of description, in order to make reader have more completely understanding to the present invention, it is provided that many certain detailJoint；But, the present invention still can may implement on the premise of clipped or whole specific detail.Additionally,Well-known step or assembly are not described in details, to avoid forming the present invention unnecessary limitSystem.In accompanying drawing, same or similar assembly will represent with same or like symbol.It is specifically intended that it is attachedFigure is only schematically, not the size of proxy component reality or quantity, and some details may be drawn the most completely,Succinct in the hope of accompanying drawing.

Refer to Fig. 1 a to Fig. 1 j, so that the phase with needle-like junction of one embodiment of the invention to be describedThe manufacture method of change memory.First, it is provided that substrate 10, it comprises access circuit 11, wherein accessesCircuit 11 comprises at least one conductive junction point (not shown).For example, substrate 10 can be silicon substrate, but notBeing limited to this, other material being suitable for can act also as substrate 10, such as ceramic material, organic material or glass materialMaterial.Access circuit 11 can comprise switch module, such as metal oxide semiconductcor field effect transistor (MetalOxide Semiconductor Field Effect Transistor, MOSFET), as shown in fig. iaThe gate 12 of MOSFET.The reading of each mnemon can be controlled by the gate voltage controlling MOSFETWrite.It is understood that the conductive junction point of access circuit 11 can be plane conductive region or be post-like conductiveConnector.Then, on substrate 10, form the first dielectric layer 20, on the first dielectric layer 20, form a sacrifice layer20a, then form at least one through hole 21 running through the first dielectric layer 20 and sacrifice layer 20a, so that access circuitThe conductive junction point of 11 is exposed via through hole 21.For example, utilize photoresist layer 100 via lithographyProcessing procedure can form corresponding multiple through holes 21, as shown in Figure 1a.In an embodiment, the first dielectric layerThe material of 20 can be oxide or nitride, such as silicon dioxide, silicon oxynitride, silicon nitride or other dielectricMaterial；The material of sacrifice layer can be polysilicon (Polysilicon).

Then, the sidewall in multiple through holes 21 forms the first barrier layer 22, such as Fig. 1 b with bottomShown in.In an embodiment, the material of the first barrier layer 22 can be titanium, titanium nitride, tantalum nitride or tantalum.LiftFor example, the first barrier layer 22 may utilize physical vapour deposition (PVD) (physical vapor deposition, PVD),Chemical gaseous phase deposition (chemical vapor deposition, CVD) or ald (atomic layerDeposition, ALD) etc. technology formed.

Then, in through hole 21, fill conductive material 23, and with multiple conductions of access circuit 11Contact electrically connects, as illustrated in figure 1 c.Same, conductive material 23 can be with skills such as PVD, CVD, ALDArt is formed.In an embodiment, conductive material can be tungsten, titanium, titanium nitride, TiAlN or titanium silicon nitride.Then, thinning sacrifice layer 20a, and make the top surface of sacrifice layer 20a planarize, as shown in Figure 1 d.Citing andSpeech, thinning sacrifice layer 20a can be with cmp (chemical-mechanical polish, CMP)Mode is realized.For example, the thickness of the sacrifice layer 20a after thinning is about 2nm to 20nm.

Then, remove sacrifice layer 20a, make part the first barrier layer 22 and conductive material 23 dash forwardFor the first dielectric layer 20, as shown in fig. le.In an embodiment, the first prominent barrier layer 22 and leadingThe height of electric material 23 approximates the thickness of sacrifice layer 20a after thinning.The method removing sacrifice layer 20a may utilizePrior art, does not repeats them here.Then, remove the first barrier layer 22 of prominent first dielectric layer 20, makeThe conductive material 23 of uncoated first barrier layer 22 highlights the first dielectric layer 20, as shown in Figure 1 f.For example,The etchants such as available CR14 remove the first barrier layer 22.The business that CR-14 is produced by Cyantek companyUpper available wet etchant, its composition is by (NH₄)₂Ce(NO₃)₆, HAc and H₂O is formed by proper proportion,It can be removed the first barrier layer 22, but the slowest to the etching speed of the first dielectric layer 20.It is understood thatThe invention is not restricted to use CR-14 etchant, the technical field of the invention technical staff can be according to the first screenBarrier layer 22 material and the first dielectric layer 20 material different, select suitable etchant, and it requires as etching theThere is high selection ratio when one barrier layer 22 and the first dielectric layer 20, in particular, select etching the first barrierLayer 22 etchant faster than etching the first dielectric layer 20.

Then, part removes the partially electronically conductive material 23 of prominent first dielectric layer 20, prominent with refinementThe conductive material 23 gone out, as shown in Figure 1 g.It is understood that the conductive material 23 not refined can be as oneHearth electrode 23a, and the conductive material 23 being refined into needle-like can be as a heater 23b.For example, conductionMaterial 23 can be tungsten, then the method for part removing conductive material 23 can be selected for hydrogen peroxide to etch conductive material23, but it is not limited to this, other Wet-type etching or dry etching technique also can reach identical effect.Same,According to the difference of conductive material, optional suitable engraving method, it requires as etching conductive material 23 and theThere is high selection ratio during one dielectric layer 20, in particular, select etching conductive material 23 than etching first JieThe etchant that electric layer 20 is fast.

Then, on the first dielectric layer 20, form the second dielectric layer 30, and cover conductive material,The most exposed heater 23b, as shown in figure 1h.For example, the material of the second dielectric layer 30 can beOxide or nitride, such as silicon dioxide, silicon oxynitride, silicon nitride or other dielectric material.Then,Thinning the second dielectric layer 30, makes the second dielectric layer 30 planarize and expose conductive material, i.e. heater 23bTop surface, as shown in figure 1i.

Finally, on the second dielectric layer 30, form the phase-transition material 40 of patterning, and with conductionMaterial (i.e. heater 23b) electrically connects, as shown in fig. ij.For example, can be prior to shape on the second dielectric layer 30Become phase-change material layer, recycling photolithography techniques patterning phase-transition material, make the phase change of patterningMaterial is formed on corresponding heater 23b.For example, the material of phase-transition material 40 can be to compriseGermanium, antimony and tellurium at least one of chalcogen compound (chalcogenide) or alloy.Chalcogen compound bagContaining having more positive electricity element or the compound of foundation.Chalcogenide alloy include by chalcogen compound and itsIts material such as transition metal etc. combine.Additionally, following alloy can act also as phase-transition material, such as gallium/antimony,Germanium/antimony, indium/antimony, antimony/tellurium, germanium/tellurium, germanium/antimony/tellurium, indium/antimony/tellurium, gallium/selenium/tellurium, stannum/antimony/tellurium, indium/antimony/Germanium, silver/indium/antimony/tellurium, germanium/stannum/antimony/tellurium, germanium/antimony/selenium/tellurium and tellurium/germanium/antimony/sulfur etc., wherein preferably is germanium/ antimony/tellurium alloy family.

In an embodiment, the manufacture method of the present invention is also contained on phase-transition material 40 formationOne top electrode 50.Form phase-transition material 40 and the top electrode 50 detailed system on corresponding heater 23bMake flow process and may utilize the realization of existing technology, do not repeat them here.

In an embodiment, processing time can be extended when removing the first barrier layer 22 or adjust suitableThe process conditions of point, so that the top surface of the first barrier layer 22 is less than the top surface of the first dielectric layer 20, such as figureShown in 2a.During follow-up refinement conductive material 23, longer needle-like heater 23b can be formed, as shown in Figure 2 b.Afterwards, according to the manufacturing step of earlier figures 1h to Fig. 1 j, structure as shown in Figure 2 c can be formed.

In an embodiment, also can extend processing time when refining conductive material or adjust suitable pointProcess conditions so that the top surface of the conductive material not refined (i.e. hearth electrode 23a) is less than the first barrier layer 22Top surface, so can obtain longer needle-like heater 23b, as shown in Figure 3 a.Afterwards, according to earlier figuresThe manufacturing step of 1h to Fig. 1 j, can form structure as shown in Figure 3 b.It is understood that it is more elongatedNeedle-like heater 23b can obtain higher electric current density, in other words, has preferably heats.Additionally,Also longer distance is had because of more elongated heater 23b between hearth electrode 23a and phase-transition material 40.Therefore,Heater 23b less likely has influence on hearth electrode 23a, and phase-transition material 40 at the heat energy of phase-transition material 40 endThe most less likely diffusion pollution is to hearth electrode 23a.

In an embodiment, after forming the needle-like heater 23b shown in Fig. 1 g, the present inventionManufacture method be also contained on the first dielectric layer 22 and form the second barrier layer 22a, cover conductive material and (i.e. addHot device 23b), and patterning the second barrier layer 22a, as shown in fig. 4 a.Afterwards, according to earlier figures 1h to figureThe manufacturing step of 1j, can form structure as shown in Figure 4 b.It is understood that the second barrier layer 22aCan prevent phase-transition material 40 from spreading the dirt caused during phase-transition material 40 heats repeatedlyDye.

In an embodiment, in the processing procedure of patterning the second barrier layer 22a, use relatively thinPhotoresistance, can not be completely covered the second barrier layer 22a, even if also the protuberance corresponding to heater 23b exposesCome.So, when part removes the second barrier layer 22a to pattern the second barrier layer 22a, conduction can be madeThe top of material (i.e. heater 23b) is exposed, structure as shown in Figure 5.Afterwards, according to earlier figures 1hTo the manufacturing step of Fig. 1 j, structure as shown in Figure 4 b also can be formed.

In an embodiment, after completing structure shown in Fig. 2 b and Fig. 3 a, according to earlier figures 4aAnd the manufacturing step of Fig. 1 h to Fig. 1 j, the structure as shown in Fig. 6 and Fig. 7 can be formed respectively.Detailed systemMake flow process, structure and technology effect as described above, do not repeat them here.

Refer to Fig. 1 j, so that the phase change note with needle-like junction of one embodiment of the invention to be describedRecall device.The phase change memory of the present invention comprises substrate 10 and at least one mnemon (memorycell).Substrate 10 comprises access circuit 11.Mnemon is arranged at substrate 10.Mnemon and access circuit11 electrical connections.Each mnemon comprises hearth electrode 23a, the first barrier layer 22 and heater 23b.End electricityPole 23a electrically connects with access circuit 11, and hearth electrode 23a is arranged in the first dielectric layer 20.First barrier layer22 are arranged between hearth electrode 23a and the first dielectric layer 20 and access circuit 11.Heater 23b extends from the endElectrode 23a, and there is a protuberance protrude from the first dielectric layer 20, protuberance is arranged at the second dielectric layer 30In, wherein the sectional area of protuberance is gradually reduced from lower to upper, that is heater 23b is a needle-like, and prominentThe end face going out portion is exposed to the second dielectric layer 30.In an embodiment, the phase change memory dress of the present inventionPut and also comprise phase-transition material 40 and top electrode 50.Phase-transition material 40 and top electrode 50 are sequentially arranged atOn heater 23b.Other detailed construction of mnemon as described above, does not repeats them here.

Summary, the phase change memory with needle-like junction of the present invention and manufacturer thereofMethod is to obtain the heater of needle-like by conductive material refinement, so can reduce between heater and phase-transition materialJunction.According to this structure, the crystalline state of little scope phase-transition material i.e. can be changed with less electric current,Therefore power consumption can be reduced.Also, the phase change scope of the phase-transition material of the present invention is less, phase change can be avoidedIssuable cavity is repeatedly heated during material operation.Additionally, sediment phase change formed material is in needle-like heaterTime, the exposed top surface of heater is a flattened condition, therefore, will not produce because of phase-transition materialFill the not exclusively problem forming cavity blemish.

Embodiment described above is only the technological thought for the explanation present invention and feature, its purposeWill appreciate that present disclosure making to be familiar with these those skilled in the art and implement according to this, when can not with restriction thisThe scope of the claims of invention, the impartial change the most generally made according to disclosed spirit or modification, mustContain in the scope of the claims of the present invention.

Accompanying drawing and symbol description used above are as follows:

10 substrates

100 photoresist layers

11 access circuits

12 gates

20 first dielectric layers

20a sacrifice layer

21 through holes

22 first barrier layers

22a the second barrier layer

23 conductive materials

23a hearth electrode

23b heater

30 second dielectric layers

40 phase-transition materials

50 top electrodes

Claims (11)

1. the manufacture method of a phase change memory with needle-like junction, it is characterised in that comprise:

Thering is provided substrate, it comprises access circuit, and wherein this access circuit comprises at least one conductive junction point；

The first dielectric layer is formed on this substrate；

Sacrifice layer is formed on this first dielectric layer；

Form at least one through hole running through this first dielectric layer and this sacrifice layer, make being somebody's turn to do of this access circuitConductive junction point is exposed；

Sidewall in this through hole forms the first barrier layer with bottom；

Fill this through hole with conductive material, and electrically connect with this conductive junction point of this access circuit；

Remove this sacrifice layer, make this first barrier layer of part and this conductive material protrude from this first dielectricLayer；

Remove this first barrier layer protruding from this first dielectric layer；

Part removes this conductive material protruding from this first dielectric layer, to refine this conductive material；

On this first dielectric layer, form the second dielectric layer, and cover this conductive material；And

This second dielectric layer of thinning, makes this conductive material exposed.

Having the manufacture method of the phase change memory of needle-like junction the most as claimed in claim 1, it is specialLevy and be, remove this conductive material in part, after refining this conductive material, also comprise:

On this first dielectric layer, form the second barrier layer, and cover this conductive material；And

Pattern this second barrier layer.

There is the manufacture method of the phase change memory of needle-like junction the most as claimed in claim 1 or 2,It is characterized in that, before removing this sacrifice layer, also comprise this sacrifice layer of thinning.

There is the manufacture method of the phase change memory of needle-like junction the most as claimed in claim 1 or 2,It is characterized in that, described method also comprises:

Form the phase-transition material of patterning in this second dielectric layer, and electrically connect with this conductive material；And

Top electrode is formed on this phase-transition material.

There is the manufacture method of the phase change memory of needle-like junction the most as claimed in claim 1 or 2,It is characterized in that, after removing this first barrier layer, the top surface of this first barrier layer is less than this first dielectric layerTop surface.

There is the manufacture method of the phase change memory of needle-like junction the most as claimed in claim 1 or 2,It is characterized in that, after part removes this conductive material, the top surface of this conductive material not refined less than thisThe top surface of one barrier layer.

Having the manufacture method of the phase change memory of needle-like junction the most as claimed in claim 4, it is specialLevying and be, the material of this first dielectric layer comprises silicon dioxide, silicon nitride or silicon oxynitride；

The material of this sacrifice layer comprises polysilicon；

The material of this first barrier layer comprises titanium, titanium nitride, tantalum nitride or tantalum；

This conductive material comprises tungsten, titanium, titanium nitride, TiAlN or titanium silicon nitride；

This phase-transition material comprises at least one of chalcogen compound of germanium, antimony and tellurium or alloy.

8. a phase change memory with needle-like junction, it is characterised in that comprise:

Substrate, it comprises access circuit；And

At least one mnemon, it is arranged on this substrate, and wherein this mnemon comprises:

Hearth electrode, it electrically connects with this access circuit, during wherein this hearth electrode is arranged at the first dielectric layer；

First barrier layer, it is arranged between this hearth electrode and this first dielectric layer and this access circuit；WithAnd

Heater, it extends from this hearth electrode, and has a protuberance and protrude from this first dielectric layer, and this is dashed forwardGoing out portion to be arranged in the second dielectric layer, wherein the sectional area of this protuberance is gradually reduced from lower to upper, and this is dashed forwardThe end face going out portion is exposed to this second dielectric layer.

There is the phase change memory of needle-like junction the most as claimed in claim 8, it is characterised in that instituteState device also to comprise:

Phase-transition material, it is arranged on this end face of this heater；And

Top electrode, it is arranged on this phase-transition material.

There is the phase change memory of needle-like junction the most as claimed in claim 8 or 9, it is characterised in thatThis device also comprises the second barrier layer, and it is arranged between the surrounding of this protuberance and this second dielectric layer, andExpose this end face of this protuberance.

The 11. phase change memorys as claimed in claim 8 or 9 with needle-like junction, it is characterised in thatThe top surface of this first barrier layer is less than the top surface of this first dielectric layer；Or, the top surface of this hearth electrodeTop surface less than this first barrier layer.